Continuity mistake: The Duncan family is forced to stay in a hotel while their termite devoured house is fixed. Dad draws up a sketch and is showing it to the family. When he brings his sketch in to show everyone, he is holding a black Sharpie, which then disappears and becomes a yellow mechanical pencil. Then the Sharpie returns for a bit, then changes back into a pencil again.
Revealing mistake: As Teddy and P.J are trying to get Charlie to act sad for their parents, Teddy tries to trick her with a sentence. However, when Teddy says the word "Party" in the sentence, you can easily see she is expressing and making the word noticeable, so that the actress portraying Charlie can follow and say the correct line moments later.
Plot hole: In the episode where Gabe wants PJ and Teddy to pretend to be his parents when his teacher wants to see them after getting in trouble at school, it is established that Gabe's elderly teacher is short-sighted. When he asks "How many fingers am I holding up" his teacher gives an incorrect answer. However, later in the episode, his teacher spots Teddy on a date at the cinema (movie theatre) and assumes she's cheating/having an affair. How could she have seen Teddy from a row in-front, when Teddy is facing the audience and not the teacher, if she couldn't see how many fingers Gabe was holding up close to her face?